Harwich has defences that date back many centuries with a number of Martello Towers and Harwich Redoubt which were built during the Napoleonic Wars.
The Port of Harwich had the following principal fortifications:
- Shotley Point Battery with 7-inch RBL guns and later 10-inch BL guns
- Harwich Redoubt with ten 24-pdr, upgraded to 68-pdr and 8-inch Howitzers. Then three 9-inch RMLs added to be replaced by 12-pdr QF guns.
- Beacon Hill Fort which was built between 1889 and 1892 for two 6-ich March VII guns and two 4.7-inch Q.F. guns.
- Landguard Fort with
Landuard Fort also had a Submarine Mining Establishment.
Harwich was designated as a Class C Commercial Harbour by the Home Ports Defence Committee in (later the Home Defence Committee) with defences to resist block ships and unarmoured cruisers. In 1905 the defences of Harwich were reported as: